KMnO4-甲醛化学发光体系测定对乙酰氨基酚

基于对乙酰氨基酚在酸性介质下对KMnO4-甲醛化学发光体系强烈的增敏作用,建立了对乙酰氨基酚的流动注射化学发光测定方法。在最佳测试条件下,方法对对乙酰氨基酚的检出限(S/N=3)为1.0×10-10mol/L,线性范围为1.0×10-9～1.0×10-5mol/L对乙酰氨基酚,相关系数R为0.9993;对1.0×10-6mol/L的对乙酰氨基酚溶液平行测定11次,其RSD为1.1%。该方法可应用于药物中对乙酰氨基酚含量的测定。     

Kinetic-potentiometric assay of formaldehyde in pharmaceutical and industrial samples, monitored by copper solid ion selective electrode, after its reaction with the copper(II)-bis-(ethylenediamine) complex

A kinetic-potentiometric method is described for the quantitative assay of formaldehyde (HCHO) in pharmaceutical and industrial preparations. It is based on the reaction of HCHO with (ethylenediamine)-Cu(II)-sulfate [Cu(CH₂NH₂)₂(H₂O)₂] · SO₄. The changes in potential, resulting from the release of the Cu(II) cations, are monitored with a Cu(II)-ion selective electrode. The calibration curve for the HCHO is linear in the concentration range 50–250 mg L⁻¹, with a limit of detection of 8.5 mg L⁻¹. The method shows very good reproducibility with an RSD of 2.6% for successive injections (n = 5) of 150 mg L⁻¹ HCHO primary solution, while it is interference free. The method was successfully tested in various industrial and pharmaceutical preparations.     

基于电纺丝法的In2O3/CdO复合材料的制备及甲醛气敏特性

用静电纺丝法制备了In(NO₃)₃/聚乙烯吡咯烷酮(PVP)纺丝前驱物, 然后分别在500、600、700℃时烧结得到三种In₂O₃ 纳米纤维. 通过X 射线衍射(XRD)仪、热重差热分析(TG/DTA)、场发射扫描式电子显微镜(FE-SEM)表征结果得知, 500℃时In₂O₃的晶相已经形成, 且粒径为最小, 约为24 nm, 纳米纤维呈介孔结构.将三种烧结温度的In₂O₃纤维制作成气敏元件, 测试对比了三种元件对甲醛气体的敏感特性, 结果表明, 500℃烧结得到的In₂O₃纳米纤维在工作温度为240℃时响应最好, 对浓度为10×10^-6 (体积分数, φ)甲醛的响应为7.用静电纺丝法合成了CdO 纳米颗粒, 通过XRD、SEM 表征得知CdO 呈粒径约为68 nm 的颗粒. 将In₂O₃和CdO以不同摩尔比(1:1, 10:1, 20:1)复合, 对比测试了纯In₂O₃及三种In₂O₃/CdO复合材料对应的气敏元件对甲醛的气敏特性, 测试结果表明当In₂O₃纳米纤维与CdO纳米颗粒以摩尔比10:1 复合时, 元件的工作温度较低(200℃), 且对甲醛表现出最佳的气敏特性, 对浓度为10×10^-6甲醛的响应为13.6, 响应/恢复时间为140 s/32s. 最后对不同摩尔比复合的In₂O₃/CdO对甲醛的气敏机理进行了初步分析.     

离子注入Pt的玻碳电极上甲酸和甲醛的电氧化

制备了离子注入Pt的玻碳电极(Pt/GC),注入剂量为5×10¹⁷ion/cm²,此电极的表面组成和各元素的浓度-深度分布用AES测量,注入Pt的价态用XPS测量.在0.5mol/LHClO₄溶液中,用Pt/GC电极和纯Pt电极研究了甲酸的电氧化行为,并在五种不同种类的电解质溶液中研究了甲醛的电氧化行为.结果表明,Pt/GC电极对甲酸和甲醛的电催化性能按真实表面积计算优于纯Pt电极.这可能与离子注入Pt过程中形成纳米团簇有关.此外,在同一电极上,甲醛在不同种类的电解质溶液中产生不同的氧化电流.说明阴离子对甲醛的电氧化过程有明显影响     

Kinetic wavelength-pair method as an alternative approach to simultaneous multi-component analysis

The kinetic wavelength-pair method involves adapting a well established principle to the simultaneous kinetic-based determination of two or more compounds with diode-array detection. It relies on measuring the difference in the rate of change of the absorbance with time at two preset wavelength pairs such that the values of these measuring parameters are the result of the contribution of one or two components. The theoretical basis adapted to first-order kinetic-based determinations was established and checked on four systems. The method thus developed was compared with other differential kinetic methods and applied to the resolution of formaldehyde-acrolein mixtures.     

High-valent [Sn(Br8TPP)(OTf)2] as a highly efficient and reusable catalyst for selective methoxymethylation of alcohols and phenols: The effect of substituted bromines on the catalytic activity

High-valent tin(IV)octabromotetraphenylporphyrinato trifluoromethanesulfonate, [Sn^IV(Br₈TPP)(OTf)₂], was used for selective methoxymethylation of alcohols and phenols with formaldehyde dimethyl acetal (FDMA) at room temperature. Different primary, secondary and tertiary alcohols as well as phenols were converted to their corresponding methoxymethyl ethers with FMDA in the presence of an electron deficient tin(IV) porphyrin. The catalyst was reused several times without significant loss of its activity.     

化学动力学中隧道效应的研究（Ⅱ）──甲醛单分子反应渠道间的相互作用研究

对甲醛单分子热反应模拟给出了分子渠道Ｅｃｋａｒｔ垒，计算了该渠道在不同温度下的隧道校正因子，研究了分子渠道与游离基渠道间的相互作用，计算了存在反应渠道间相互作用时各渠道的Ｋ＿（ｕｎｉ）（ｉ）、Ｅａ（ｉ），分子渠道考虑隧道效应，而游离基渠道无隧道效应，计算结果与实验结果一致。     

酒类中微量甲醛的快速测定新方法

在FeCl3存在条件下,甲醛与自制蛋白液显色剂能生成紫色化合物,藉此可以定量测定微量甲醛。方法线性范围为1~10μg/10mL,线性相关系数r2=0.996,检出限为0.05μg/mL。用该法测定经活性炭脱色的啤酒和白酒中的甲醛含量,回收率为96.46%~103.32%,相对标准偏差为1.36%~2.09%(n=6)。     

乙基橙-溴酸钾体系动力学光度法测定痕量甲醛

研究了在稀H2SO4介质中,痕量甲醛催化KBrO3氧化乙基橙褪色反应的适宜条件和影响因素,建立了测定痕量甲醛的动力学光度法。方法采用固定时间法于507 nm波长处测量体系的吸光度,在适宜条件下,ΔA与甲醛质量浓度具有良好的线性关系,方法的线性范围为0~0.24 mg/L,检出限为0.004 mg/L。该方法用于饮料、废水和废气中痕量甲醛的测定,测定结果的相对标准偏差RSD≤3%(n=6),回收率为102%。     

The detection of formaldehyde in textiles using interdigitated microelectrode array diffusion layer titration with electrogenerated hypobromite

An interdigitated microelectrode array (IDA) was applied to the determination of formaldehyde released from textiles produced in industry. The proposed method is based on formaldehyde reaction with hypobromite which is formed in weakly basic media by control current electrooxidation of bromide on the generator segment of the IDA array. The unreacted hypobromite diffuses through the gap between individually polarisable IDA segments and it is amperometrically detected on the collector segment of the IDA. The efficiency of this nonconvective transfer process in the absence of formaldehyde was substantially higher (78%) in comparison with that when using the rotating ring disc electrode. The influence of the added formaldehyde on the transfer process can be utilised to develop a simple and sensitive analytical procedure for formaldehyde detection with a detection limit of 4×10⁻⁶ mol dm⁻³.